1. Field of the Invention
The present invention relates generally to a method of connecting two components and more particularly to a method for connecting components by deforming the material of one component into a hole in the other component.
In the production of numerous objects, of which we shall mention here just household appliances and motor vehicles, two components which bear on one another in a planar manner in the area of the connecting point are to be connected to one another. For example, a clip may be fixed to a motor-vehicle body or a bearing bush to a washing machine wall, or the like. A technique referred to as "projection welding" is most frequently used in such cases, but riveting and screwing ar also commonly employed.
Compared with the other techniques, projection welding has the advantage that the components remain fluid-tight, which is desired or even necessary in many cases. But it has the disadvantage that, in the case of parts coated on the surface, depending on the type of coating, either welding is not possible at all without pretreatment or else, in particular in the case of galvanized steel parts, the zinc coating is damaged in the area of the weld.
2. Description of the Relevant Art
U.S. Pat. No. 3,828,517 discloses a method of connecting a relatively thin first component to a relatively thick second component in which, in first, separate operations, the thin component is perforated and if need be provided with a chamfer, the thick component is subjected to an extrusion operation in such a way that a rivet fitting into the hole is integrally formed and finally, during the actual connecting, the rivet is inserted into the hole and the rivet head is formed on the side of the thin component remote from the thick component. If, during the connection of two components of different thickness, it is desired to provide the recess not in the thick component but in the thin component, for example for aesthetic reasons, this known method cannot be used, since not enough material can be driven through for forming the rivet head.
This also applies to the method in which an apparatus according to EP-A-155,618 is used.
German Patent Specification 918 090 discloses a connecting method of two workpieces wherein exterior positioning means are provided to hold the workpieces, one thereof being plasticly deformed into a tapering hole of the other. The material to be deformed must be transferred from the outer side of the workpiece in direction to the other workpiece with the result that extremely high deformation forces are required.